RF/Microwave Instruments Evolution: From Professional Hardware Into Amateur Kit and Software-Defined Radio

Introduction

Recently, RF/microwave technologies have been widely implemented and have become indispensable necessities in our daily work, such as 4G/5G communication network, Internet of Things (IoT), Wi-Fi, Bluetooth, mobile phone, Internet, QR code of personal whereabouts record during the coronavirus (COVID-19) pandemic, and RFID-based security system in work offices. In addition, IoT (operating frequency range from a few hundred MHz to 7.125 GHz) has been broadly applied to different public and industrial fields including machine health monitoring, Industry 4.0, asset monitoring, agriculture monitoring system, asset tracking, environmental monitoring/control, machine-to-machine (M2M), autonomous driving, vehicle to everything (V2X), and delivery truck tracking, passenger car tracking, route development. Therefore, future electrical and electronic engineers will inevitably get involved directly or indirectly in the field of telecommunications.

At the same time, the development of monolithic microwave integrated circuit (MMIC) and microprocessor technology has become increasingly mature and improved in terms of operating frequency, bandwidth, transmit/receive RF power limitation, thermal resistivity, baud rate, power consumption, and several functionalities. The integration of MMIC and programmable microprocessor with the assistance of software can produce software-defined based RF instrument, so-called software-defined radio (SDR), which can be used for the above-mentioned applications. Hence, the use of MMIC components becomes more common, demand increases, and mass production, prices have reached an affordable level. On the other hand, the programmable microprocessors or devices, such as application specific integrated circuit (ASIC), field programmable gate array (FPGA), digital signal processor (DSP), and general purpose processor (GPP), allows the production of higher quality, compact, and cost-effective multi-function SDR.

This has attracted many RF/microwave communication amateurs, enthusiasts, and emerging companies to participate in the development of SDR, such as USB-based RF signal source, portable power sensor, PC-controlled RF transceiver, amateur spectrum analyser (SA), and compact PC-based vector network analyser (VNA) in the past two decades. The USB-based amateur RF test instrument was initially launched on a small scale in 2005, with an operating frequency of up to 100 MHz, such as Tentec TAPR VNA. From 2005 to 2007, several small-scale new companies (Array Solutions, Mini Radio Solutions, and OMICRON Lab) produced USB-based devices with a maximum operating frequency of 180 MHz. The main reason was that there were no commercial high-frequency MMIC synthesizer chips on the market at that time (although commercial power detection chips had reached several GHz at that time, such as AD8302 gain & phase detector up to 2.7 GHz released in 2001). Later, with the increase in the operating frequency of MMIC synthesizer chip products (up to 4.4 GHz) in the market, from 2008 to 2012, more and more established and emerging companies actively involved in the RF/microwave instrument business, such as National Instruments, Copper Mountain Technologies, AEA Technology Inc, Quonset Microwave, Protek Instrument Co., Ltd, LA Techniques Ltd, Triarchy Technologies, Vaunix Technology, Aaronia AG, RF Explorer, DEEPACE, Windfreak Technology, Signal Hound.

Hence, the evolution of the RF/microwave test equipment is directly affected by the development and demand of communication technology, such as specifications, built-in functions, prices, sizes, and control or operation methods of the test instruments. This chapter surveys and reviews in detail the release of new test instrument products, the participation of new company's in the test instrument business, the test instrument business model, prices, specifications, and test instrument control/operation in the past two decades.